Apparently, on the N5K, the SPAN function can induce back-pressure on the ingress interface.
Does this happen with any other platform? Searching www.cisco.com, seems to me that this only applies to the N5K ... but perhaps this effect has only been /documented/ for the N5K ... perhaps it happens on other platforms. Does anyone know?
"If the SPAN source interface sends more than 6-Gbps traffic or if traffic bursts too much, the device drops traffic on the source interface. You can use the switchport monitor rate-limit 1G command on the SPAN destination to reduce the dropping of actual traffic on the source interface; however, SPAN traffic is restricted to 1 Gbps."
"SPAN traffic is rate-limited as follows on Nexus 5500 series switches to prevent a negative impact to production traffic:
SPAN is rate-limited to 5 Gbps for every 8 ports (one ASIC).
RX-SPAN is rate-limited to 0.71 Gbps per port when the RX-traffic on the port exceeds 5 Gbps."
I've been poking at this question intermittently ... and I'm stumbling in finding a definitive source 'knowledge base' article.
Still, at the moment, it seems to me that the N5K has a unique feature here, the ability to shield ingress (source) traffic from the contention induced by a SPAN port.
I don't see a similar feature on the C4K or C6K, for example (i.e. rate-limiting SPAN ports).
In thinking about this, it seems to me that one needs to understand the architecture of the switch in order to assess the potential for impacting source traffic. So, for example, if one is SPANning a port on a typical C4K line card (8 10/100/1000 ports sharing a single 1Gps uplink to the Sup card) *and* one is mirroring to another member of the same 8 port group, then it seems like to me that the source port would discard frames, assuming that the source port is pushing past 50% of that 1 Gps uplink.
That being said, I have a buddy who believes the C6K is fairly immune to this effect, on account of some aspect of its switching design.
Am I on the right track here, in terms of figuring out (a) how to assess potential impact to source traffic, and (b) in claiming that only the N5K has this SPAN rate-limiting command?
Before I go leaving sniffers SPANning 10Gb/s ports for long periods of time, I want to understand the risk of impacting production traffic.
Listen: https://smarturl.it/CCRS9E24 Follow us: https://twitter.com/CiscoChampion
Cisco Radio Aware Routing addresses several of the challenges faced when merging IP routing and radio communications in mobile networks, especially those exhibiti...
Listen: https://smarturl.it/CCRS9E23 Follow us: https://twitter.com/CiscoChampion The Wi-Fi 6E Catalyst 9136 access point takes advantage of the 6-GHz band to produce a network that is more reliable and secure, with higher throughput, more ...
When moving from OSPFv2 to OSPFv3, there are many changes in the format of the LSAs Type, but the most known changes are: IP prefix informations are no longer carried in Type-1 LSA and Type-2 LSA, new LSAs Type 8 and 9 are added to carry these prefixes.
Read a preview of my book OSPF The ultimate for CCIE Enterprise and Infrastructure exam in Books Google Doc.
Read a preview of my book OSPF The ultimate for CCIE Enterprise and Infrastructure exam in Books Google Doc #CCIE #Cisco #exam #Enterprise ...
Question 1: What are the OSPF Loop Prevention Mechanisms
In single area, the routers have the Link State Database, having the same LSDB helps the routers to build a loop-free topology.
Now in a multiarea topology, the ABRs are respon...